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difference between .exe and .com
Name: ravi Date: November 15, 2002 at 23:24:34 Pacific OS: any OS CPU/Ram: 32
Comment:
what is the difference between .exe and .com files?
Name: sekirt Date: November 15, 2002 at 23:34:43 Pacific
Reply:
There are a few differences. Don't know that much, but .COMs are limited to 64K and they are supposed to run faster. I also think that DOS gives priority to .COM. So, if you had 2 programs with the same name, the .COM would run first.
I am sure someone will know much more. sekirt
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Response Number 2
Name: w Date: November 15, 2002 at 23:43:01 Pacific
Differences between .COM and .exe programs involve the following: Program size Segmentation Initialization Program size .exe programs may be virtually any size. .COM programs may only be 64K, including the PSP. Segments .COM program combines the PSP, code, data and stack segments. .exe program the code, data and stack segments must be defined by the programmer. Initialization .COM programs are required to begin at 0100H. Use the ORG 0100H directive to accomplish this task. .exe programs are automatically loaded above the PSP area (0100H).
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Response Number 3
Name: John Date: November 16, 2002 at 00:00:43 Pacific
Reply:
If what you are sayin is true then why can you change regedit.exe to regedit.com it it still runs?
Regedit is 116K? It will still run if you change the file exten to .com!
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Response Number 4
Name: sekirt Date: November 16, 2002 at 00:16:53 Pacific
Reply:
It does not change the contents of the program, or alter the structure. But it is a trick that works.
sekirt
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Response Number 5
Name: John Date: November 16, 2002 at 00:19:29 Pacific
Reply:
Its a trick that works, but it goes over the 64 limit?
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Response Number 6
Name: sekirt Date: November 16, 2002 at 01:04:31 Pacific
Reply:
It does not change the structure. Just that command.com recognizes it as a program to run. And does run it.
Can't give you a technical explanation. It was suggested to try that (years ago. DOS version 2.11, when I read it.) that it might run faster
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Response Number 7
Name: sekirt Date: November 16, 2002 at 01:17:40 Pacific
Reply:
A better question might be, why is COMMAND.COM larger (93,890 bytes) than 64k?
sounds like something left over from the days of a 64k memory maximum, couldn't find any reference to it on the net, other then database files that are limited to 64k and the work arounds for those in c++
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Response Number 9
Name: sekirt Date: November 17, 2002 at 19:23:28 Pacific
Reply:
In case anyone is interested, I did get a response in the programming forum.
Summary: My friend has Windows XP Home Edition and his .exe and .com file associations were deleted. I can't open command.com, regedit.exe, notepad.exe, .reg files, or system restore. His computer didn't come ...
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